Neuroscientific updates: the earlier, the better for second (foreign) language learning?
In The Applied Linguist's first ever article in 'The Neuroscientist is In' series, we explore in depth the science behind early exposure to a second language, and crucially, whether earlier is necessarily better.
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In an era where cultures become increasingly intertwined, a question that often pressures parents is when to expose their young children to a second (or foreign) language. Those who introduce their children to extra-early bilingualism believe there is science to back up their decision, while those opposed to the idea argue that early bilingualism may bring nothing more than confusion and lack of interest for the first language. Both sides intuitively believe that their concerns are valid, which is why the gathering of various scientific perspectives is so crucial.
The reason that this debate exists largely has to do with what 'better' entails to begin with. Do we speak of 'better' in terms of proficiency development? Ease of acquisition? Less confusion with the L1? Or 'better' in terms of strengthening neural reserve? Can 'better' be defined by numbers, or is it somewhat value-based? Depending on what matters most to us personally, the argument could differ.
If we were to start with 'ease of acquisition', there is ample evidence that a child's neuroplasticity is more flexible and adaptable in response to new learning stimuli. This explains why your children would likely take up Spanish much more quickly than your grandfather if they were to start their learning together. Having that said, part of all this depends on the aspect of language. It has been discovered that although L1 and L2 phonetic processing involve more or less the same neural circuitry, the development of L2 phonetics (i.e., the sounds of language) for example is likely more sensitive to age than, say, vocabulary building. This is because children's auditory pathways (and motor pathways, for that matter) function better in comparison with that of older learners. In early childhood, extensive exposure to foreign sounds may lessen a child's neural commitment to the acoustic properties of the first language, which may translate to more flexible adaptability to L2 phonetics.
It is also helpful to note that although an early start does bring along some added benefits, the road to native-like mastery of phonetics, syntax, vocabulary, and language use in general depends on other factors as well. The quality and nature of L2 input (i.e., what the L2 input is like), level of use (i.e.,how often L2 exposure occurs), and context of use (i.e., whether the exposure happens in a natural or deliberate context) can all play a pivotal role still. Whether or not the method of learning is engaging enough for a child to learn with motivation is also an underestimated aspect to consider.
Looking at early vs. late bilinguals more generally, neurobiological evidence seems to strongly imply the advantages of starting things early. Dementia researchers have found that the increase of Alzheimer's Disease biomarkers (Aβ and tau ) in older people's cerebrospinal fluids are alleviated in bilinguals, and early bilinguals seemed to benefit more in this regard.
The investigation into this question fires on still and weighing the different lines of evidence, I personally would lean towards early bilingualism being the 'better' choice. However, this is not to discourage the value of picking up a language at a later age . From my research perspective, early bilingualism is perhaps not as valuable as a continuous (even daily) effort to engage in a second or foreign language over the course of a lifetime, as such effort is truly what keeps the brain alert, active, and going at all times.